There are two rational justifications for the application of electrochemical redox control in isolated organ perfusions. The first is to protect the organ from prolonged exposure to an oxidative perfusate and the second is to minimize ischemic damage incurred by the donor organ by supplying redox control at reoxidation. The proposed is aimed at facilitating longer organ perfusion time and increasing the tolerance of the organ toward ischemia through redox control. The study may be viewed in three major parts: Aim 1: To establish optimal redox conditions for the recovery of harvested ischemic kidneys and for their long-term storage. Evaluation of the treated kidneys will be by: a) perfusion characteristics; b) electronmicroscopy; c) measurements of perfusate enzymes; d) post-perfusion metabolic study (oxygen, lactate and pyruvate consumptions); and e) kidney function by serum creatinine. Aim 2: To design a new disposable redox cell using Reticulated Vitreous Carbon in place of platinum and to design a battery-operated portable potentiostat to drive the cell. These new designs are intended for clinical application in future studies. Aim 3: To perfuse human donor kidneys, which were found not acceptable for human transplantation because of excessive ischemic damage, in order to establish the role of electrochemical redox control in the reversal of this ischemic injury in the human kidney (such kidneys will be used for laboratory study only and will not be reconsidered for transplantation in this proposal). These kidneys will be studied in pairs with one treated only and then evaluated as described in Aim 1, parts a-d, and by analysis of ATP, ADP and AMP.